refactor(empty-state): 空状态支持内容居中

lib/pages/recommend/recommend_page.dart

@@ -348,6 +348,7 @@ class _RecommendPageState extends State<RecommendPage>
         key: const Key('recommend-feed-empty'),
         icon: Icons.movie_outlined,
         title: l10n.noStories,
+        stretchContent: true,
       ),
     );
   }